A student conducts an experiment to determine how the amount of water given to a plant affects its growth.

Which of the following is not a constant or control for this experiment?

a.

the type of plant

b.

the amount of soil

c.

the amount of water

d.

the amount of time in the sun

I might be wrong, but I think it's the amount of water.

c. the amount of water

Explanation:

As the student is trying to determine how the amount of water given to a plant affects its growth, that can not be a constant, since that is the thing that he should change, giving different amounts of water to see how it affects its growth, all the other options should be constant they should have the same amount of time in the sun, the same amount of soil and they should be the same type of plant, so the differences in growth be caused only by the different amounts of water.